Fossa Carolina

Between the Altmühl and Rezat rivers at the village of Graben (a district of Treuchtlingen), you will find one of the greatest technical and cultural monuments of the early Middle Ages – the FOSSA CAROLINA (or Karlsgraben in German). What still remains today is a 500-metre-long stretch of water and the earth retaining walls, which are still testament to the first ever attempt to connect the Rhine and Danube rivers by canal.

In 793 AD, Charlemagne gave orders to excavate a canal of approximately 3,000 metres in length to make it easier for ships to get to the south-easterly reaches of his empire and to help get supplies to the Franconian army.

The Fossa Carolina has been designated one of the top 100 geological sites in Bavaria by the Bavarian State Ministry of the Environment.

A walk around the Fossa Carolina, starting at the information board in Graben, is highly recommended. This circular route is about two kilometres long and provides a close insight into the geography and history of the waterway. At the end of what is now left of the ditch, right at the watershed, there is a fountain where the whole family can have a go at pumping water.

Would you like to have a go at routing water by hand to the North Sea or the Black Sea? The watershed fountain makes it easy. The water runs through a stone fountain either to the left into the Altmühl-Danube system towards the Black Sea or to the right into the Rezat-Regnitz-Main-Rhine system towards the North Sea.

At the end of the circuit, have a look at the Fossa Carolina exhibition, which is housed in a former barn called the ‘Hüttinger Scheune’.

Fossa Carolina exhibition

The Fossa Carolina exhibition in the Hüttinger-Scheune barn is a colourful display using new media to reconstruct the development of the Fossa Carolina more than 1,200 years ago.

The exhibition has some unusual exhibits, which are testament to the settlement of the local area during the Carolingian Empire and explain the political background behind the construction of the canal.

The exhibition also provides information on the geology of the region and displays rocks and soil samples, which helped geologists to discover more about the origins of the watershed at Treuchtlingen.